Diversification of the industrial structure has been demanding a rapid increase in the volume of working at severe low temperature and special low temperature environment; such working as electric power development, oil drilling, fire fighting and security-related work in extremely-cold season, working in the freezer and refrigerator throughout the year, as well as forestry, fishery, railway-truck maintenance and cargo-handling at harbor in winter.
Thick clothing made up of air-containing materials, for example, feather and wool is used for clothing to be used when working under the low temperature environment. Recent years have seen a development of the surface and lining clothes comprising synthetic fibers such as polyester and polyamide, combined with (hollow) synthetic fibers insulator, metallic composite sheet and synthetic foam, taking advantage of lightweight and excellent workability.
However, arctic clothing made of conventional synthetic fibers such as polyester and polyamide has no problem when used under the less severe temperature of about 5 to -5 degrees Celsius. However, these materials will be hardened under the working conditions of -10 to -15 degrees Celsius; their heat-insulation (cold-insulation) is insufficient, and long-time working is difficult. Furthermore, the feather and wool withstand the working conditions of a temperature of -20 to -30 degrees Celsius, but turn brittle below -30 degrees Celsius. The most fatal defects are heavy weight, poor workability and weak strength.
On the other hand, aramid fiber is excellent in heat-resistance, flame-retardancy and strength, and has found an extensive application in the clothing to be used by the personnel who may have to be exposed to flame. In this case, combination with other fire-retardant fiber and mixture between meta-aramid fiber and para-aramid fiber are also known.
It has not been known, however, that aramid fiber has excellent heat-insulation (cold-insulation, that is, super heat-insulation in the low temperature environment.) The aramid fiber as heat-insulator (cold-insulator) for arctic clothing has not been used in practice so far.
Furthermore, arctic clothing used under various working environments as mentioned above is required to be high-performance anti-static clothing, preventing static electricity and dust to be accumlated in order to control various problems resulting from static electricity.